Circle-dividing instrument



2 Sheets-Shut 1 W. H. HOLLOPETER 0111013 DIVIDING INSTRUMENT Findlay 27, 1925 Sept. 21 1926.

W. H.H OLLOPETER.

w. H. HOLLOPETER 7 CIRCLE DIVIDING INSTRUIENT FiLQd It! 27, L925 2 Sheets-Shoot 2 w. H. HOLLOPETER.

Patented Sept. 21, 1926.

UNITED STATES PATENT OFFICE.

WILLIAM H. HOLLOPETER, OF PORTLAND, OREGON.

cIRoLE-DIviDING INSTRUMENT.

Application filed '27, 1925. Serial No. 33,130.

' ting can be easily made by an unskilled per- The fourth object is to so construct the parts that extremea'ccuraey can be obtained with very little efi'ort,

These, and other objects, will become more apparent from the specification following as illustrated .in the accompanying drawing. in which I Figure 1 is a plan of the instrument showing it in operation. Figure 2 is an end elevation showing the pencil arm. Figure 3 is a front elevation. I cal section taken along the line 14 in Figure 1. Figure 5 is an enlarged view Of the scale arm. Figure 6 is an enlarged elevation of the dividing head. Figiire'lisa side view of Figure 6 of which Figur 8 is a plan with a portion cut away for clearness. Figure 9 is a rear elevation of Figure 6. Fi ure 10 is a still further enlar ed detail of the tracing wheel. 7

Similar numbers of reference refer to the same parts throughout the several views.

Referring in detail to the drawings, for

the purpose of illustrating the device it is shown on a piece of paper 11 upon which a rest its legs 12 which support the round base 13 having a downwardly extending stem 14 and an upwardly extending stem 15 whose uppermost end 16 is threaded. A vertical in 17 is slidably mounted in the base 13. The stem .15 serves as a pivot for the bar. 18 which is preferably provided with bosses 19 for hearing purposes. A thumb nut 20 is placed on the end 16 of the stem 15 to hold the bar 18 in place.

Figure 4; is a verti- On the end 21 of'the bar 18 is slidably placed the marking head 22 which can be clamped in desired position by means of the thumb screw 23. On the lower side of the marking head 22 is formed the stud 24 on which is pivoted the arm 25 which is held in place by means of the washer 26-, and the nut 27. On the under side of the driving end 28 of the arm 25 is formed a boss 29, through which passes the threaded shank 30 ofthe pin 31 which is provided with a hole 32 for. the rod 33. A set screw 34 in the pin 31 is used to clamp the rod 33 in thedesired position. A washer 35 a nut 36 hold the shank 30 in place.

On the marking end 37 of the arm is mounted a pencil arm 38 to which it is hinged by means of the vertical belt 39 which is threaded into the ,boss 40. A penoil holder 41 is hinged to the peneil by means 'ofthe horizontal pin 42-. A sp in 43 is heldv by the head of the bolt '39 ah nrges the pencil arm downwardly. 'Alead holder 44 is threaded through the split end 45,'th'rough which end passesthe'clamping .screw 46. A threadedplunge-r47 is used to t eedthe leads l l dtlt of the holder" 41- 1 jlhe dividing end 48 of the bar 18 is'provided with a serrated edge 49 mac ines the slid able dividing headed and has is handle 51 on its upper side. Ontheunder side oi the'jhead is formed a bracket .52 through which asses the threaded axle 53, on whose threaded end is placed alocl; hilt 5&1. preferably knurled, as is the head 55. The latter is pro' ided with gradtiations 56. A pointer 57 is fastened to the bracket by means of the soiewsss On the sale 53' is mounted atr'acing wheel which is held in place by the washer 60 and nut 61.

In one side of the tracing wheel 59 is provided an outei circle of index holes 62 which, in this instance, are twenty-fivein number. Ah intermediate circle of five holes 63 and an inside circle with .the one hole64 are also Provided.

.Passiiig vertically through the head 50 is a rod .65having a number of V grooves 66' forniedthereinand having a head 67 formed rocker arm 69, which is held in place by the washer ai d the nut 71. I a 'The end 72 of the arm 69 carries a small lllU 'there'cn, andalso having its end 68 shouldered and threaded to form a pivot forthe,

roller adapted to engage one circle of holes 62, (33 or 64 at one time, depending upon the vertical position of the rod 65. This is determined accurately by the pointed screw 74 which engages the grooves 66.

The end 7 5 of the rocker arm 69 is provided with a vertical screw 76 on which is hinged the arm 77. The arm 7 7 can be clamped rigid to the member 69 by means of the screw 7 6. On the outer end of the arm 77 is mounted the rotatable pin 7 8 on whose shank 79 are placed the washer 80 and the nut 81'. v

The hole 82 receives the rod 33 which may be clamped to the pin 78 by means of the screw 83. The spring 84 is attached to the bracket 52 by means of the screw 85 and bears against the arm 69 at its junction with the arm 77.

On the side of the head 50, in front of the notches 86 in the serrated edge 4-9, is threaded the tubular member 87 whose flanged portion 87 is graduated, as shown. Bearing in the member 87 and partly in the head 50 is a pin 88 whose shank 89 carries a spring 90 and passes through a hole in the member 87 and has pinned on its projecting end the knurled head 91 which is provided with an index arm 92 whose point 93 can engage the holes 94 on the member 87 An eccentric point 95 is formed on the pin 88 and is adapted to slidably engage the notches 86.

On top of the member 18 alongside of the serrated edge 49 are placed three scales 96, 97 and 98. The circle 99, Which is being divided, is indicated on the paper 11, as Well as the imaginary circle 100 along which the measurements are made. Readings on the scale are made along the side 101 of the member 50. Notches 102 in the circle 99 indicate the divisions which have been made.

The operation of the device is as follows: Given a circle to divide into forty parts the point of the pin 17 is place-d in the center of the circle 99, which is to be divided. The point 95 is now moved and rotated on its axis until the side 101 of the dividing head 50 is on the graduation marked 40 on the scale 97 and the point 93 is in the serrated hole in the member 87". The pencil point is now adjusted for height and radius by means of the plunger 47 and the screws 3 and 83. V

The roller 7 3 is now moved to the intermediate circle of holes 63 in which there are five holes, as above stated.

lVhen the'head 50 is in the position above described, the tracing wheel 59 is adjusted four inches from the center of the circle 100. The diameter of the tracing wheel 59 is one unit, which, in this instance, happens to be inches, therefore it follows that it will revolve eight times at every complete journey around the circle 100. Since the wheel 59 is provided with five holes 63 in the circle in whose path the small roller 73 rides, it also follows that this roller will drop into five holes at each complete revolution of the tracing wheel, making forty holes into which the roller will drop at every complete revolution of the dividing head about the pin 17.

Through the arm 69, the rod 33 and the arm 25 motion is transferred to the pencil point causing same to make sharp notches 102 in the circle 99, thereby clearly defining the intersection of the dividing lines.

Let us now suppose that 201 divisions are required. The point 93 is now set at 1 while'the side 101 remains on the 200 line on scale 98. The roller 7 3 is now moved to the outer row of holes 62.

It will be discovered that the dial is only employed when using the scale 98 in which the ten values given on the dial represent the ten divisions of any of the smallest spaces on the scale 98.

In order to offset discrepancies which might arise in the use of this'device owing to wear on the tracing wheel, soft paper or temperature changes a micrometer adjustment is provided for the tracing wheel. This is secured by rotating the head 55 the desired amount.

It will be apparent to anyone understanding the principle on which this instrument operates that the same results could be gained in a great variety of ways from the one above described without departing from the spirit of my invention; I therefore do not wish to limit myself to this precise form of the device, but I intend to cover allsuch forms and modifications of same as fall fairly within the appended claims. I

1. In a circle dividing instrument, the combination of a central pivot; a bar mounted across said pivot; a marking means mounted on one end of said bar; a dividing head on the opposite end of said bar adapted to actuate said marking means at every division of a circle; and a connecting means between said marking means and dividing head.

2. In a circle dividing instrument, the combination of a central pivot; a. bar mounted across said pivot; a marking means mounted on one end of said bar; a tracing wheel having a unit diameter mounted under the opposite end of said bar; trip means mounted with said wheel; and operating connections between said trip means and said marking means.

3. In a circle dividing instrument, the combination of a central pivot; a bar mam. bly mounted on said pivot having one end thereof calibrated; a marker on the plain end of said bar having means for adjusting its distance from said pivot; a dividing-head slidably mounted on the calibrated end of said bar; a tracing wheel under said dividing head; a rocker arm mounted on said dividing head; means between said Wheel and rocker arm for rocking said arm; and means connecting said rocker arm and said marking means adapted to momentarily deflect said marker from its path at each complete or fractional revolution of said tracing Wheel.

4:. In a circle dividing instrument, the combination of a central pivot having a paper-engaging point; a bar rotatably mounted on said pivot, one end of said bar having a plurality of scales consisting of sets of calibrations marked thereon, the opposite end of said bar being plain; a marker on the plain end oi said bar adjustable With relation to the paper and pivot; a dividing head on the calibrated side of said bar; and a tracing Wheel on said div'ding head one division of whose circumference, as determined by index holes. is evenly divided into a circle traversed by said tracing Wheel when said head is set at a calibration on the corresponding scale representing the number of divisions desired.

'5. In a c1rcle dividing instrument, the

combination of a central paper-engaging pivot; a flat bar rotatably mounted on said pivot near itsmiddle, said bar having one end calibrated and the same end provided With notches corresponding With said calibrations; a dividing head slidably mounted over the notched portion ofsaid bar means for adjusting the position of said head on said barbetween said notches; a paper-engaging Wheel supporting said head, said Wheel having a plurality of circles of concentrioholes formed in its side; a rocker arm on said head having a roller on one end thereof; means for moving said roller into engagement with the holes of any of said circles; a pencil-holding arm on the plain end of said bar; and a rod connecting said rocker arm and said pencil arm.

WILLIAM H. HOLLOPETER; 

